European team discovers smallest extrasolar planet

London, Feb 4 (IANS) A European satellite has discovered the smallest planet outside of our solar system, which is twice as large as earth and orbiting a star slightly smaller than the sun.The planet is believed to be composed of rock and water, and takes 20 hours to orbit its host star, the shortest orbital period of all exoplanets found so far.

Astronomers infer its temperature over 1,000 degree Celsius, hot enough to make it covered in lava or superheated water vapour.

Most of the 330 or so exoplanets discovered so far are giant planets, primarily composed of gas, like Jupiter and Neptune. This new object, named CoRoT-Exo-7b, is very different, said an LESIA release.

“Finding such a small planet wasn’t a complete surprise,” said Daniel Rouan, from Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (LESIA) in Paris, who announced the discovery on Tuesday.

Alain Leger from the Institut d’Astrophysique de Marseille, leader of the discovery paper, explained: “It could be an example of a so-called ocean planet, whose existence was predicted some years ago. A Neptune-like planet, made of ice around a rocky core, drifts so close to its star, the ice melting to form a fluid envelope.”

Such small planets are extremely difficult to detect.

The discovery will be the published in the journal Astronomy and Astrophysics.